Roughly translated and abbreviated; ASH? WHAT ASH? *#/! ASH!, was the conversation between the Anchorage control tower and the KLM pilot who had the misfortune of flying through a volcanic ash cloud on a December morning in 1989. It was dark, as it is most December mornings in Alaskan North.

SEM image of an ash particle erupted by Redoubt volcano on March22, 2009. The image was acquired by Pavel Izbekov and Jill Shipman using ISI-50 Scanning Electron Microscope at the Advanced Instrumentation Laboratory, University of Alaska Fairbanks. / Courtesy the University of Alaska Fairbanks Geophysical Institute and the Alaska Volcano Observatory, U.S. Geological Survey

This is how the transmission between the control tower and the KLM flight from Netherlands went:

Alaska Volcano Observatory was created in 1988. “But it wasn’t until that morning that we began operating as an observatory and we’ve been operating ever since” recounts Game McGimsey. Game tells the story in FrontierScientists video Redoubt’s Ash.

Despite losing power to all four engines for eight minutes and dropping two miles from about 25,000 feet, the KLM flight landed safely at Anchorage International Airport. The 231 lives on the KLM survived the terrifying incident. The 747 KLM suffered $80 million damage and its engines had to be replaced.

This is the extreme edge of the MTSAT view for the satellite which is over the equator in Asia. / Courtesy Jonathan Dehn, National Weather Service

Alaska contains 130 volcanoes. 90 of those volcanoes have been active in the past 10,000 years and might be expected to erupt again. Based on information provided by the Federal Aviation Administration, more than 80,000 large aircraft per year, and 30,000 people per day, are in the skies over and potentially downwind of Aleutian volcanoes on the heavily traveled great-circle routes between Europe, North America, and Asia. Volcanic eruptions from Cook Inlet volcanoes (Spurr, Redoubt, Iliamna, and Augustine) can have severe impacts, as these volcanoes are nearest to Anchorage, Alaska’s largest population center.